BOSTON, Mass. — Rebekah DiMartino took the stand this week, looked directly at the man authorities say detonated a bomb that ripped her body apart and told her story.

After DiMartino left the courtroom she did something else. DiMartino took to Facebook where she posted an open letter telling the accused bomber “you saved my life.”

DiMartino’s leg was destroyed by shrapnel and debris in April 2013. Since that time, she has undergone 16 surgeries and once believed she would never walk again.

On Wednesday, she walked into court and faced Dzhokhar Tsarnaev to tell her story. In her open letter, this is how she described the experience:

“I got to walk into a courtroom and take my place at the witness stand, just a few feet away from where you were sitting. (I was WALKING. Did you get that?) And today I explained all the horrific details, of how you changed my life, to the people that literally hold YOURS in their hands. That’s a little scary right? And this afternoon before going in, I’m not going to lie..my palms were sweaty. And sitting up there talking to the prosecution did make me cry. But today, do you know what else happened? TODAY…I looked at you right in the face….and realized I wasn’t afraid anymore. And today I realized that sitting across from you was somehow the crazy kind of step forward that I needed all along.”

In the letter, DiMartino describes Tsarnaev as a coward and a little boy who wouldn’t look her in the eyes:

“If your eyes would’ve met mine for just one second, you would’ve also seen that what you “blew up” really did BLOW UP. Because now you have given me (and the other survivors) a tremendous platform to help others, and essentially do our parts in changing the world for the better.”

DiMartino also acknowledges Tsarnaev did take a part of her:

“But in so many ways, you saved my life. Because now, I am so much more appreciative of every new day I am given. And now, I get to hug my son even tighter than before, blessed that he is THRIVING, despite everything that has happened.”

DiMartino signed her letter, “Someone you shouldn’t have messed with” and #bostonstrong.